Supports Placement for Resin 3D Printing

September 21, 2017

Getting Started for Resin 3D Printing Support Placement

One of the first things which will hit you when getting started with slicing for 3d resin printing is how different it is, especially if you had done a lot of slicing for FDM printing before. As opposed to a right-side up print common to all FDM type printing,

For this quick walkthough on preparing the a resin 3d printed model, we will be using the B9Creator software which is available here. We’ll use this to add the necessary supports to a 3d model and re-export it as a new STL file for printing via NanoDLP.

After installing and opening B9Creator, a small window pops up with these 3 options – we shall only be using the Layout mode.

Adding and Orienting the 3D Model

In the Layout mode, there will be a representation of your build plate. First things first, we will need to get the model imported. This is done via the Add models button in the left panel.

Here’s our test model dropped straight onto the layout plate. The key thing to remember here is the build plate will be upside down and your model will be as such too.

There are a list of rather self-explanatory text boxes in the left panel too which allows you to adjust the position, orientation and scaling of your 3d model.

Here, we have moved and rotated the 3d model as shown, for the following reasons:

Due to the suction forces of the resin peeling from the tank, we will want to make sure that every cross-sectional layer of the print is as small as possible. This will reduce the off-chance that the model gets stuck too firmly to the base of the resin vat and shakes or worst, dislodges the print.

Another thing to note will be to orientate the model such that its most features of the model should ideally point no more than 45 degrees. This is to give further layers something to build upon. This is simliar to the concept in FDM 3d printing too.

You may also notice that the model has been lifted up vertically around 5mm – this is for us to get some vertical height under the model to start the next step of supports addition.

Adding Supports to the Model

Whilst there is an automatic support generation option – this tends to do really badly in creating any usable support structures. So it’s best to go manual on this one.

Next up, it’s the fun task of deciding where to anchor the supports of the model to the build plate. This is done by selecting the Supports sub panel in the left. The first things will be to add some heavy supports as these are the main robust anchors which will ensure your piece stays in place. These are typically added to the base part of the model.

However, in some instances, the distance between the bottom of the model and the base plate may be insufficient for supports to be added, resulting in the bottom part of the support “piercing” through. If this happens, simply go back to orienting the model and moving it up a tad.

There we go, that’s better. Two or three more of these heavy supports will make it steady enough to add on the rest of the support we need.

One of the key principles of adding the rest of the supports is to ensure that there isn’t any “islands” of new model which was not previously attached to the any other parts of the model.

There is a handy feature in B9Creator which displays white lines which represent the parts of the same height. In the example above, the bottom of the backpack will be printed as “islands” without any other part of the model joined to it. This is a prime example of where you will need to put in supports to hold them up. In this case, Medium supports will suffice.

Here, we’ve almost added in all the supports needed. In some of the areas, light supports will be sufficient to hold things up and yet be easy enough to remove.

Modifying Supports

As a hint – it’s important to double check that the supports added don’t inadvertently clip into your model itself. The example above shows a heavy support which has cut right into part of the model. This is really bad.

Luckily, it is also easy enough to fix if spotted. Simply go into support modify mode, select the offending support and click on Medium to take it down a notch.

There we go – much better. Sometimes, if this doesn’t work there are also the options to modify and make the selected support vertical or straight. Worst case, there is always the option of deleting the problematic support entirely and giving it another shot.

Another thing to take note of is when the base of the support lands on the model itself. Not a problem in itself, but would be worth the time to double check that the base part does not land on a detail which is required and can be cleaned off nicely.

Results Time

If all goes well for the print, you should be able to get something which looks like this.

With a nice rinse in IPA, support removal and then post curing in UV – here’s the final piece! Well worth all the effort 🙂